Development of a Four-Fin Bio-Inspired UUV: CFD Studies

The development of an unmanned underwater vehicle (UUV) with four actively controlled curvature flapping fins is described. Three dimensional unsteady flow computations past several configurations of the vehicle are computed and based on the minimum drag a nearly elliptical cross-section with a smooth leading and trailing sections was obtained. The hydrodynamic characteristics of this vehicle at NRL are computed for a range of operational conditions and a dynamic mode of this vehicle was created for the development of a controller. Detailed parametric studies were carried out varying several physical and kinematic parameters, such as separation of the two fins, the phasing of the rear fin with respect to the front fin, the vehicle speed, and the fin orientation. The unsteady flow solver is coupled to a 6-DOF model to simulate an unconstrained yaw and dive maneuvers of the vehicle. The original document contains color images.